CHANaES IN PLUMAGE OF ZOSTEROPS OiERULESCENS — NORTH. 99 



collected or sent me for examination has prepared a series of 

 nearly fifty skins in every stage of plumage. The result of my 

 observations conclusively prove that the Z. ivesternensis of Quoy 

 and Gaimard, the type of which was obtained by them at Western 

 Port, Victoria, is only the spring and summer attire of Z. ccvrules- 

 cens of Latham. Taking the two extreme phases of winter and 

 summer plumage exhibited in Z. ccerulescens, it can be easily 

 understood why each phase should be thought to belong to a 

 distinct species ; and it is only where one has these birds under 

 daily observation, and obtains specimens during every month of 

 the year that the intermediate stage, or the gradual transition of 

 one phase of plumage to the other, is observed. These changes 

 in the plumage of Z. ccerulescens have already been pointed out 

 by me in a series of skins exhibited in August last at a meeting 

 of the Linnean Society of New South Wales. Typical examples 

 of Latham's Z. ccerulescens,* with the deep tawny-buff flanks and 

 grey throat, the autumn and winter attire of this species, may be 

 obtained in the neighbourhood of Sydney from the middle of 

 April until the end of August. Some specimens, however, are to 

 be found during Ajoril that have not quite lost their summer 

 plumage, and in August others that have already began to attain 

 their spring livery ; these birds have the yellow throat more or 

 less clearly defined. Usually the first indications of losing the 

 deep tawny-buff flanks and acquiring the yellow throat are seen 

 during a normal winter, about the second week in August, in 

 some seasons a fortnight earlier, but in two specimens examined 

 the grey throat was retained as late as the 19th September. 

 During August and September, however, the gradual transition 

 from the winter to the spring attire (the Z. westernensis of Quoy 

 and Gaimard),! is slowly taking place, and by the middle of 

 October not a bird is to be seen with the deep tawny-buff flanks 

 and the grey throat. Specimens shot in November have the 

 throats of a brighter olive-yellow than at any other period of the 

 year ; the flanks at that time being of a very pale tawny-brown. 

 At mid-summer, when the breeding season with the species is 

 virtually over, the throat is slightly paler than in the spring, and 

 this livery is retained until the beginning of March. The flanks 

 then become darker, increasing in intensity of colour from that 

 time forward, the yellow feathers on the throat also disappearing 

 and passing into grey until the autumn livery is again fully 

 assumed by the end of April. 



Of six specimens obtained at Table Cape, Tasmania, during 

 April, 1894, three have the throat grey, the remainder faintly 

 washed with yellow, and in all of them the flanks are of a deeper 

 tawny-buff than in Australian examples. 



* Z. dorsalis (Gould), Bds. of Aust., iv., p. 81. 

 t Voy. de TAstrolabe, pi. 11, fig. 4.. 



